Bone is a supporting material for the body's framework and conserves the necessary bone mass and structure. Bone also functions as a reservoir of calcium (Ca2+) or the like, and plays an important role in maintaining calcium level in the blood. Bone is in a dynamic steady state of bone remodeling, which maintains a delicate balance by continuously performing both bone resorption and bone formation. Bone remodeling is a complex process involving bone formation by osteoblasts and bone resorption and degradation by osteoclasts, thereby maintaining a physiological and metabolic balance. However, the balance between bone resorption and bone formation is disrupted by various factors and diseases, leading to osteoporosis.
Osteoporosis is a bone disease which results from a disturbance in the balance between bone resorption and bone formation, caused by having a higher degree of bone resorption relative to bone formation. This disease frequently occurs in middle-aged or elderly women. Osteoporosis reduces calcification of bone tissues, and decreases the level of compact substances in the bone, which broadens the marrow cavity, and causes reduction in bone density or bone mass, resulting in decreased bone strength. Consequently, as osteoporosis progresses, bone becomes brittle, and fracture may easily occur even with a small impact. Bone fracture is associated with an increased mortality rate of patients with osteoporosis, and also causes serious problems such as negative impact on patients' quality of life. Thus, various strategies have been established to produce drugs capable of increasing bone density and decreasing of the risk of bone fracture.
Bisphosphonate (alendronate, etidronate), hormones (raloxifen), vitamin D, calcitonin, calcium agents, or the like have been used as anti-osteoporotic agents, and Forteo™, a form of parathyroid hormone responsible for bone formation, is currently used to treat advanced osteoporosis. However, they are known to have adverse effects. Specifically, hormone agents must be administered throughout the patient's life, and in the case of long-term administration, side effects may be induced such as breast cancer, uterus cancer, gallstones and thrombosis. Vitamin D agents are expensive and show little efficacy, and calcitonin agents are also very expensive and difficult to administer. Calcium agents have few side effects, but their effectiveness is restricted to prevention of osteoporosis, not treatment. Forteo™, a commercially available parathyroid hormone, has an advantage in that it stimulates bone formation, whereas other known drugs are restricted to prevention of bone resorption. However, Forteo™ should be given as a daily injection for a long period of time, and may increase the risk of osteosarcoma. Its application is also restricted due to its relatively high price.
Bisphosphonate agents show low absorptivity and may induce esophagitis, and thus should be taken with a sufficient amount of water before meals. In addition, patients should wait at least 30 minutes before ingesting other beverage or food, and avoid lying down for a prescribed amount of time following administration. Such agents are also reported to increase risk of hypocalcemia. Recent studies have suggested problems such as reduction in bone turnover rate due to excessive inhibition of bone resorption, inhibition of bone formation, gastrointestinal disorders and osteonecrosis of the jaw. Furthermore, it has recently been reported that long term administration increases the risk of bone fractures.
As described above, the current therapeutic agents for osteoporosis have drawbacks, so there is a need for development of osteoporosis drugs and therapies which have reduced disadvantages or side effects. Natural products from plants and organisms have frequently been used as sources for development of effective drugs. There is increased interest, for example, in analysis of natural products from marine organisms. US Patent Publication No. 2003066083 provides a novel extract (mussel hydrolysate) prepared from the Indian green mussel (Perna viridis), which can inhibit osteoclast differentiation in murine haemopoietic precursors of monocyte/macrophage cell lineage. U.S. Pat. No. 7,387,781 provides a composition for treating osteoporosis and osteoclast formation, comprising C. Sinensis mycelium as the effective ingredient.
Deer velvet antler and deer velvet antler blood (DVAB) are famous traditional Chinese medicines commonly used as tonics against stress and fatigue. However, no prior art references teach or suggest that deer velvet antler and DVAB have benefits in regard to osteoporosis.